China's Chalco starts work at Guinea bauxite mine

* Aluminum Corp of China Ltd,, known as Chalco, said on Monday it had officially started construction work on its Boffa bauxite mine in Guinea.

* Groundbreaking ceremony was held on Sunday morning local time in Guinea, state-run Chalco says in a statement.

* First phase of the project will produce 12 million tonnes per year of bauxite, a rock refined to produce alumina, which is used to make aluminium.

* Chalco said in June it planned to start production from the mine by the end of 2019.

* Chalco parent Chinalco did not respond to a request for comment on Monday after Rio Tinto said a 2016 agreement for it to acquire Rio’s 45.05 percent stake in Guinea’s Simandou iron ore project had lapsed. (Reporting by Tom Daly; Editing by Kirsten Donovan)